I'm a novice dwarf fortress player and I had some ideas I wanted to try for my first serious dwarf fortress, but I had some questions about fortifications in this game. I wanted to build a defense in my fortress that it looks like so:
M M M M M M M M M M
FFFFFFFFFFFFFFFFFFFFFFFFF
........................................
........................................
XXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXX
........................................
........................................
FFFFFFFFFFFFFFFFFFFFFFFFF
M M M M M M M M M M
Enemies would walk along the 3-tile wide ground represented by the 'X's. The periods represent 'open space', marksdwarves are represented by the 'M's and the fortifications are represented by the 'F's. I'd have open spaces so that ranged enemies wouldn't be able to stand right next to my fortifications and shoot my marksdwarves. My concern was whether stray shots from my marksdwarves would have a fairly likely chance of passing through the fortifications, wounding dwarves on the other side. Does anyone know?
Also, I wanted to build a perimeter wall around my entrance and build second-story fortifications on top of those walls with wooden flooring built along the fortifications inside so that marksdwarves could stand and shoot from the second story. Would the fortifications block my dwarves' ability to shoot down a z-level? If the answer is "No", I'm not sure about how fortifications affect sight/firing angles but I think it's logical that the dwarves wouldn't be able to shoot straight down from the wall. It's hard to explain so I'll make a visual again:
M F
-------
| | E
..............................
This is a side-shot of what I had in mind. The marksdwarf (M) is behind a fortification (F) while standing on a floor (-) built along the wall (| |) trying to shoot an enemy (E) at ground level (...) who is standing right next to the wall. Is that firing angle "valid"? If not, would I need to build a moat (I think I'd probably build one anyways for aesthetics) and how many tiles wide would it need to be, minimum?
Thank you for reading and (hopefully) answering.